ID 36 – Somatosensory evoked potentials in juvenile myoclonic epilepsy with tremor and essential tremor

Abstract

Objective Many clinicians may encounter juvenile myoclonic epilepsy (JME) patients complaining of tremor. The etiology and generators of this tremor are not clear. We aimed to evaluate if there were differences or similarities between JME tremor and ET by using somatosensory evoked potentials (SEP). Methods We analyzed the median SEPs of 14 patients with JME complaining of hand tremor, 14 patients with ET, and 14 healthy volunteers. Tremors were also assessed by accelerometric recordings. Results The N20-P25 and P25-N35 amplitudes were significantly higher in the JME group as compared to other groups. In three siblings in the JME group “giant SEPs” were observed. Moreover left N20, P25 latencies were significantly longer in ET group. Tremor frequencies of both groups showed some overlap but ET had a distinctive pattern whereas JME patients had mild interrupting myoclonus. Ten JME patients were using VPA, but their tremor had started earlier. Conclusions The SEP amplitudes of two patient groups are different even though they have the tremor as a common symptom. Our findings might be interpreted as there are two different pathophysiological mechanisms associated with this similar symptom in JME and ET patients. Key message Same complaint, different SEP findings.